Rough chop the eggplant, red onion, and red bell pepper into bite-sized pieces. Place in a large bowl together with cherry tomatoes, sea salt, oregano, olive oil, and black pepper. Mix until well-combined.
Place all the veggies (and fruit) onto a large baking sheet. Slice the garlic head in half (width-wise) and place the two halves on the baking sheet. Place in the oven and bake for 45 minutes, until veggies are beginning to brown.
Place all the roasted veggies into a large bowl together with cannellini beans. Stir everything together. Take 1/3 of the mixture and place it in a separate bowl, together with the yogurt. Blend with an immersion blender (or use a regular blender) until you get a sauce (it isn't meant to be perfectly smooth).
Toast your bread and slather with sauce. Add a couple slices of heirloom tomato. Top with unblended bean and veggie mixture. Top with bits of fresh basil, more cracked black pepper, and a drizzle of olive oil.